// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.

#include "util/arena.h"

#include "gtest/gtest.h"
#include "util/random.h"

namespace leveldb
{

    TEST(ArenaTest, Empty) { Arena arena; }

    TEST(ArenaTest, Simple)
    {
        std::vector<std::pair<size_t, char *>> allocated;
        Arena arena;
        const int N = 100000;
        size_t bytes = 0;
        Random rnd(301);
        for (int i = 0; i < N; i++)
        {
            size_t s;
            if (i % (N / 10) == 0)
            {
                s = i;
            }
            else
            {
                s = rnd.OneIn(4000)
                        ? rnd.Uniform(6000)
                        : (rnd.OneIn(10) ? rnd.Uniform(100) : rnd.Uniform(20));
            }
            if (s == 0)
            {
                // Our arena disallows size 0 allocations.
                s = 1;
            }
            char *r;
            if (rnd.OneIn(10))
            {
                r = arena.AllocateAligned(s);
            }
            else
            {
                r = arena.Allocate(s);
            }

            for (size_t b = 0; b < s; b++)
            {
                // Fill the "i"th allocation with a known bit pattern
                r[b] = i % 256;
            }
            bytes += s;
            allocated.push_back(std::make_pair(s, r));
            ASSERT_GE(arena.MemoryUsage(), bytes);
            if (i > N / 10)
            {
                ASSERT_LE(arena.MemoryUsage(), bytes * 1.10);
            }
        }
        for (size_t i = 0; i < allocated.size(); i++)
        {
            size_t num_bytes = allocated[i].first;
            const char *p = allocated[i].second;
            for (size_t b = 0; b < num_bytes; b++)
            {
                // Check the "i"th allocation for the known bit pattern
                ASSERT_EQ(int(p[b]) & 0xff, i % 256);
            }
        }
    }

} // namespace leveldb

int main(int argc, char **argv)
{
    testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}
